We establish the average wavelength dependence for rough-surface reflectance S_rs(λ) in Lake Superior and determine its magnitude at any individual site by extrapolating the total reflectance or raw remote sensing reflectance R_rsT(λ) measured at the surface to the asymptotic limit of zero scattering where S_rs(λ) ≅R_rsT(λ). The results show that S_rs(λ) differs from the flat-surface Fresnel reflectance of sky radiance used in standard determination of the remote sensing reflectance R_rs(λ) attributed to the scattering of light by particles and molecules in bulk water. In waters containing colored dissolved organic matter (CDOM), R_rs(λ) can be very low and radiometric measurements at ground level can often lead to negative estimates of R_rs(λ) if we assume simple mirror-like reflectance of the sky radiance as the basis for correcting radiometric data for surface reflectance. We examine the differences between Fresnel reflectance and S_rs(λ) and estimate the ratio of the concentrations of CDOM versus suspended particles that could produce negative values of R_rs(λ) if assume Fresnel reflectance in calculation of R_rs(λ).

We examined diets of fishes from gillnet and egg pump collections conducted on reefs in western Lake Erie during walleye (Sander vitreus) egg incubation periods from 1994–1999 and 2004 to assess incidence of walleye eggs in fish diets. We collected no potential egg predators in samples taken in 1994 but from 1995–1999 and in 2004 we caught 22 different species of fish on reefs in addition to spawning walleye. In most years, white perch (Morone americana) stomachs contained more walleye eggs than any other species on the reefs averaging 253 eggs per stomach. We also found lower numbers of walleye eggs in the stomachs of channel catfish (Ictalurus punctatus; 53 eggs/stomach), johnny darter (Etheostoma nigrum; 2 eggs/stomach), logperch (Percina caprodes; 10 eggs/stomach), quillback (Carpiodes cyprinus; 184 eggs/stomach), rock bass (Ambloplites rupestris; 3 eggs/stomach), round goby (Neogobius melanostomus; 4 eggs/stomach), sculpin (Cottidae; 21 eggs/stomach), silver chub (Macrhybopsis storeriana; 3 eggs/stomach), spottail shiner (Notropis hudsonius; 14 eggs/stomach), trout-perch (Percopsis omiscomaycus; 30 eggs/stomach), white sucker (Catastomus commersonii; 20 eggs/stomach), and yellow perch (Perca flavescens; 181 eggs/stomach). Similar to other studies of predation on walleye eggs, our results indicate that prolonged incubation periods increase the potential for egg loss due to predation.

Steelhead (Onchorhynchus mykiss) have been stocked in Ohio tributaries to Lake Erie for over a decade yet little information on the value of this fishery exists. A steelhead angler intercept survey was conducted in fall, winter, and spring of 2002–2003. Almost 77% of the anglers surveyed (375) responded to a mail survey with useful information. Typical steelhead anglers were 46 years old, middle class, male, and had 9 years steelhead angling experience. Less than two-thirds of respondents fished with spinning tackle and one-third used fly tackle. On average, individuals traveled with 1.7 people in their group. They mostly took single day trips (94% of respondents), traveling approximately 84 kilometers round trip. Steelhead catch rates are positively related to number of trips taken, angler experience, number of streams visited per trip, number of hours fished per trip, and type of tackle used. The value of the steelhead angling experience to participating anglers is estimated at $36 to $46 per trip while the money spent to participate in steelhead fishing is estimated at $26 per trip. Annual value of the Lake Erie tributary steelhead fishery in Ohio could be as high as $12 to $14 million compared to the $600,000 cost for the stocking program. The fishery provides economic benefits to the coastal areas where adequate access for stream steelhead anglers exists during parts of the year when recreational demand is lowest. This information can be used by policy makers to justify expenditures on stocking, public access, and water quality improvements that enhance angling.

Evidence suggests larval yellow perch, Perca flavescens, utilize nearshore and offshore habitat during the 30–40 day period between hatch and transition from pelagic to demersal habitat. In a large, open system like Lake Michigan this represents a significant increase in available habitat and it is important to understand how this increase may impact our ability to sample larval yellow perch in an unbiased manner. We measured the vertical distribution of larval yellow perch in southern Lake Michigan as a function of size, age, and diel period. Larval yellow perch were collected from two zones (surface and epilimnion) from 1 to 32 km from shore in 2001 during the day; on four dates surface samples were also collected at night. Results indicate larval perch are more abundant at the surface at night than during the day. Larval yellow perch < 15 mm total length (TL) and younger than 18 days post hatch were found in both surface and epilimnion habitat during the day, but larvae > 15 mm TL were captured only in the epilimnion and farther than 5 km from shore, which suggests a different spatial distribution for larger, older larvae. Diel differences in larval abundance and size at the surface suggest more and larger larvae will be caught for a similar effort at night as compared to daytime sampling. Observed differences in larval distribution with size and age also suggest that sampling concentrated nearshore and/or at the surface has the potential to under-sample larger/older yellow perch larvae in Lake Michigan.

The spatial distribution of 17 metals in the sediments of the Detroit River was established using metal concentrations from a river-wide survey. The survey (1999) was based on a stratified random sampling design that divided the river into upper, middle, and lower reaches and subsequently into U.S. and Canadian sides of the river. Results based on strong extraction, using concentrated acids, revealed that the Lowest Effect Level (LEL) for As, Cd, Cu, and Hg was exceeded at more than 75% of sampling sites and the Severe Effect Level (SEL) for As at 16.2% of sites. Most of the metals were homogenously distributed throughout reaches of the river, although sites with elevated concentrations were localized mainly along the middle and lower reaches as a result of a pattern of contamination sources and geographic complexity of the river, especially a spatial/temporal variability in water flow. A comparison of the results of a strong to a weak extraction (cold 5% acetic acid, to assess metal bioavailability) revealed two groups of sediment type. The first group with a “high” weak/strong ratio (bioavailable metals; about 1 for Ca, Mg, Na and from 0.6 to 0.4 for the rest of metals) was observed at sites with low flow velocities below 0.4 m s⁻¹. The “low” ratio (non-bioavailable metals; 0.25 for Ca, Mg, Na and from 0.15 to 0.05 for other metals) was observed at sites with flow velocities greater than 0.6 m s⁻¹. The data indicate that the sediment conditions, dependent on flow distribution, regulate not only the distribution of heavy metals but also can regulate metal bioavailability.

Conventional and newly-developed techniques to determine the phosphorus (P) status of Lake Ontario phytoplankton were employed in September 2003, immediately after the passage of the storm system associated with Hurricane Isabel. Surface water (1–5 m) was collected at 29 stations, with selected stations sampled throughout the water column. Chemical estimates of total P concentrations were compared with proxies of P bioavailability: P enrichment bioassays of lake water, alkaline phosphatase activity (APA), and P-dependent bioreporter assays. Average total P (314 nM) and total chlorophyll-α (2.12 μg/L) concentrations measured in pelagic surface waters from throughout Lake Ontario suggest an oligotrophic status prevailed across much of this lake during the sample period. Autotrophic picoplankton (0.2–2 μm) displayed the highest growth rates and were grazed at the highest rate, whereas P-enrichment bioassays favored the production of autotrophic nanoplankton (2–20 μm) and autotrophic microplankton (> 20 μm) biomass. Average concentrations of bacteria (2.61 ×10¹⁰ cells/L) were higher than those measured during summer in a similar lake (Erie), whereas the average viral density (1.38 ×10¹⁰ virus particles/L) was similar. Pelagic stations exhibited higher APA than coastal stations; cyanobacterial bioreporter responses did not show high correlation with APA suggesting that proxies of P-demand based on residual effects (e.g., enzyme production) were not indicative of shorter-term biological responses related to planktonic growth (bioreporter genetic response). The combination of traditional chemical, biochemical (APA), and cutting-edge biological methods (bioreporter) provided information on nutrient concentrations and primary productivity throughout Lake Ontario, while concurrently allowing real-time assessment of P bioavailability.

The Soil Water Assessment Tool (SWAT) was implemented to determine annual sediment yields and critical source areas of erosion for the Buffalo River Watershed. Model calibrations were performed by comparing simulated streamflow discharge and sediment concentrations against measured values. Monte-Carlo simulations were performed to identify the most sensitive parameters and the “best-fit” parameter ranges. This study especially highlighted the importance of snow parameters, which, previously had not been identified as sensitive for model simulations. The cover (C) and practice (P) values for croplands had to be reduced considerably from default model values to constrain simulated sediment yields within the observed data range. The model did not simulate an ice-scour event which generated a substantial amount of sediment. The average annual sediment yield simulated by SWAT for the Buffalo River watershed (108,593 ha) amounted to 0.8 tons/ha/yr. The Cazenovia Creek subwatershed contributed the largest portion (45%) of the total sediment yield from the Buffalo River watershed. We attribute the higher sediment yields from Cazenovia Creek to the greater proportion of steep slopes in this subwatershed. The accuracy and reliability of SWAT sediment predictions at the small watershed (second order or less) and storm-event scales will depend on the accuracy of input information, especially the resolution of the landuse-landcover (LULC) layer, the number of rainfall stations used in simulations, and the number of internal sites against which the model has been calibrated.

We determined diet composition, feeding strategy, prey size, and effects of prey type on food weight and energy in stomachs for lake whitefish Coregonus clupeaformis in Lake Huron during 2002–04. Age-0 lake whitefish (73–149 mm TL) ate mainly large-bodied cladoceran zooplankton in the summer (July–mid September). Medium lake whitefish (≤350 mm TL excluding age-0) generally ate soft-bodied macroinvertebrates, especially Chironomidae larvae and pupae, in the spring (mid May–June). Zooplankton, if eaten, were generally most important in the summer. Molluscs were generally a minor part of medium lake whitefish diets. Large lake whitefish (> 350 mm) mainly ate molluscs, particularly quagga mussels (Dreissena bugensis), despite geographic differences in mussel abundance. Large-bodied crustaceans (Diporeia spp., Mysis relicta, Isopoda) were a minor part of large lake whitefish diets. Lake whitefish demonstrated a flexible feeding strategy, with individual specialization on some prey and generalized feeding on others. The size of benthic prey (Diporeia spp., Chironomidae, and Dreissena spp.) eaten increased with fish size and influenced the energetic value of prey for medium and large lake white-fish. The type of prey eaten affected the food and energy intake differently for each size class of lake whitefish. Age-0 lake whitefish that ate mainly zooplankton had more food and energy in stomachs than fish eating shelled prey or other macroinvertebrates. On the other hand, food weight in stomachs did not differ across prey groups for medium fish, but energy in stomachs was lowest for fish that ate shelled prey. For large lake whitefish, there was no difference in food weight or energy in stomachs for different prey groups.

Declines in juvenile American eel (Anguilla rostrata Lesueur) abundance have led to concern about the impacts of anthropogenic structures on eel migration patterns. Telemetry provides an insightful tool for examining the movements of eels around these structures. Although there have been a number of studies investigating movements of Anguillid eels, using a variety of transmitter attachment techniques, there are few published evaluations of the effects of various tag attachment procedures. Hence, the effects of three telemetry attachment procedures were evaluated for female silver phase American eels. Short-term effects were examined by comparing the swimming performance of control eels and surgical shams with the swimming capacity of eels tagged externally, internally, and gastrically 24-hours following surgeries. Adaptive effects were investigated using a second swim trial 8 to 10 weeks following surgical procedures. Additionally, 12-week transmitter retention rates were calculated for each attachment method. Critical swimming velocity was not significantly different between treatments (P > 0.05), but did decrease significantly between trials (P = 0.012), suggesting that the swimming capacity of silver-phase American eels is not affected by the presence of telemetry transmitters or the method of transmitter attachment, even though swim performance decreases. However, transmitter retention rates varied considerably after the 12-week experimental period. Three gastric tags were regurgitated for a 12-week retention rate of 72.7%. No surgically implanted transmitters were shed, while 11 out of 12 externally affixed transmitters were lost, resulting in a retention rate of only 9.1%. These results suggest that surgically implanting transmitters is the preferred method of affixing telemetry transmitters to American eels, especially for long-term telemetry studies.

Coastal bluff recession continually threatens homes, roads, and land. In areas where coastal development is increasing, an understanding of variability in bluff recession is critical to coastal management. In this study bluff recession rates and beach and bluff lithology and morphology are characterized at 28 sites along the Wisconsin coastline of Lake Superior. Bluffs are composed of clay, sandy clay, clayey sand, sand, and sandstone, and range from 1.1 to 37.3 m in height. Beach composition at the sites varies from sand to a mix of sand and cobbles, to cobbles and boulders, and beach slopes are between 3 and 14°. Bluff-crest recession rates between 1966 and 1998, measured from aerial photographs, range from 0.07 to 0.57 m/yr. Field measurements of wave runup at the study sites were conducted to verify wave runup estimated from available methods in the literature. An index, cumulative wave impact height (CWIH), which accounts for the frequency, magnitude, and duration of waves impacting the bluffs, is used to assess the degree of correlation between this measure and bluff recession rates. The average yearly CWIH (CWIH) for the 1966–1998 epoch is correlated with the recession rates from the same period. Reasonable correlations between CWIH and recession rates at sites throughout the study area are found when comparing bluffs of similar lithology and height. These results suggest that bluff recession rates in this area are not only linked to wave impact at the bluff toe but also lithology, which affects a bluff's response to wave attack at the toe as well as other processes (e.g., gully erosion) that promote recession.

Cercopagis pengoi, a zooplanktivore first discovered in Lake Ontario in 1998, may reduce availability of prey for planktivorous fish. Cercoapgis pengoi is most abundant in late summer and fall. Therefore, we hypothesized that abundance of small zooplankton (bosminids and cyclopoids) species would decrease at that time. To determine if the establishment of C. pengoi was followed by changes in the zooplankton community, seasonal patterns in nearshore zooplankton collected from May to October 1995–2000 were examined. Early summer density of small zooplankton was similar in all years while late summer and fall densities were significantly lower in 1998–2000 than in 1995–1997. The declines of small zooplankton coincided seasonally with the peak in C. pengoi density. Other possible causes for the observed changes in small zooplankton are less likely. High levels of fish predation should have resulted in smaller zooplankton in 1998–2000 than in 1995–1997 and larger declines in Daphnia than other groups. This was not observed. There was no significant decline in chlorophyll-α concentrations or changes in temperature between 1995–1997 and 1998–2000. Therefore, the declines in density of small zooplankton were most likely the result of C. pengoi predation. The effect of C. pengoi establishment on alewives is increased competition for zooplankton prey but C. pengoi has replaced a portion of the zooplankton biomass and adult alewife diet formerly dominated by Diacyclops thomasi and Bosmina longirostris.

Beach closings are a growing concern in coastal regions because of serious public health and economic ramifications. Two beach sites separated by 150 m of shoreline on Lake Michigan were monitored in the summer of 2003 and 2004 for E. coli densities to evaluate the potential outcome of relocating an existing beach to a site immediately to the south. Under identical weather conditions, there was a large disparity between the two sites for 25 of the 39 days tested, where E. coli levels at the existing beach were at least twice as high as those at the proposed beach. Following rainfall, E. coli levels at the existing beach increased up to 100-fold to levels as high as 4,500 CFU/100 mL, whereas only a 10-fold increase in levels was observed at the proposed beach site. Water exchange in the beach areas was predominantly from wind driven currents rather than dilution, and longshore current speed at the proposed beach was calculated to be twice that of the existing beach. Stormwater and combined sewer overflow (CSO) discharged from two closely spaced outfalls approximately 0.5 km north of the existing beach was found to have E. coli levels above the EPA recommended limit of 235 CFU/100 mL for recreational waters. However, this input did not appear to be a major influence on beach monitoring results. In some cases, E. coli levels at the beach did not exceed 235 E. coli/100 mL during a CSO. Defining the sources and spatial range of pollution inputs would allow beach monitoring results to be interpreted in a more meaningful context, which may lead to the formation of effective management strategies.

Northern Lake Tanganyika is characterized by an almost permanently stratified water column which causes severe nutrient depletion in surface waters. Any external N source to surface waters, therefore, is of importance in sustaining primary production. This study attempted to quantify riverine input of dissolved inorganic nitrogen (DIN) to the extreme northern end of Lake Tanganyika (surface = 900 km²) as well as the DIN uptake by surface phytoplankton. Results showed that riverine DIN inputs (1,930 tons of N/year) were of similar importance to atmospheric deposition (1,520 to 1,720 tons of N/year) and were maximal during the dry season. Moreover, seasonal DIN variations in river and lake waters showed maximum concentrations during part of the dry season (May to July 1999) probably due to high atmospheric inputs. Phytoplanktonic nitrate and ammonium uptake rates were measured during nine cruises and varied from 0.01 to 19.3 nM/h. These values suggest that uptake by phytoplankton in the surface waters could represent a DIN sink of about 14,400 tons of N/year, thereby utilizing all available DIN coming in from external sources. External DIN sources represent approximately 25% of the annual phytoplankton N requirements, showing the major importance of unquantified N sources in sustaining primary production in the northern basin of Lake Tanganyika. These sources could include organic N present in the external sources, and internal N supply.

The relationships between metallothionein-like protein (MTLP) and tissue metal (Ni, Cd, Cu, Zn, Pb) concentrations were examined in Oligochaetes and Chironomid larvae collected from reference and metal contaminated sediments. Tissue metal concentrations, for example, Cd reaching 0.3 μmol/g in oligochaetes and Cu, reaching 0.8 μmol/g in chironomids collected from Great Lakes reference sites (Environment Canada) indicated the presence of bioavailable metal at some sites. The concentration of MTLP ranged from 3.3 (± 1.0) to 11.5 (± 4.5) nmol MTLP/g in oligochaetes, and 2.7 (± 1.0) to 8.0 (± 2.7) nmol MTLP/g in chironomids. Individually, tissue metal concentrations were relatively poor (r² = 0.002–0.52) predictors of MTLP, but when multiple metals were used the relationship became stronger (oligochaetes r² = 0.84, p < 0.001; chironomids r² = 0.61, p < 0.001), suggesting that MTLP was induced by multiple metals. Tissue metal and MTLP concentrations in invertebrates from the metal contaminated slips of Collingwood Harbour were not elevated above reference levels, indicating that only a fraction of the metal in the sediment is bioavailable. Chironomids collected from lakes contaminated by atmospheric fallout of smelting emissions (Rouyn-Noranda, QC) had elevated tissue metal concentrations but MTLP concentration did not consistently reflect elevated tissue metal. Overall, MTLP concentrations in invertebrates collected from metal-contaminated sites were not significantly higher than concentrations in reference site-collected invertebrates. The data presented here suggest that, at some sites, MTLP concentration in field-collected organisms would be a useful surrogate for tissue metal but, because of a lack of detailed taxonomy (organisms were designated as chironomids or oligochaetes) and the relatively small sample sizes of this study, no definitive conclusion regarding the suitability of MTLP concentration as a field-based biomarker of metal exposure can be made without further study.

Muskegon Lake was designated an Area of Concern because of severe environmental impairments from direct discharge of industrial and municipal wastes. Since diversion of all municipal and industrial wastewater in 1973, few studies have assessed ecological changes associated with improved water quality. We examined distributions and long-term changes in the benthic macroinvertebrate community at 27 sites. Distributions were evaluated relative to distance from the river mouth, water depth, grain size, and known areas of sediment contamination. Temporal changes were assessed relative to wastewater diversion. Oligochaeta and Chironomidae dominated the community, and the oligochaete trophic condition index indicated that, in 1999, the lake was generally mesotrophic to eutrophic. Cluster analysis resulted in four distinct site groupings. A cluster of sites near the river mouth had the highest total density (9,375 m⁻²) and lowest diversity (Shannon Weaver Index 1.05) suggesting an enriched habitat. A site cluster in the south central region had the lowest oligochaete density (2,782 m⁻²), lowest oligochaete trophic condition index scores (1.00), and highest diversity (2.24), suggesting the best habitat. The chironomid community in this site cluster was dominated by predatory species, possibly resulting from high concentrations of heavy metals at some sites. Densities of all major taxonomic groups increased significantly between 1972 and 1999. Decreasing proportions of oligochaetes (0.85 to 0.68) and increasing diversity suggest improved environmental conditions over this period. Evidence suggests that changes in Muskegon Lake's benthic community were more a result of wastewater diversion than Dreissena invasion.

While chemical control of zebra mussels (Dreissena polymorpha) has proven effective in closed systems, the high dosages required for adult eradication restricts the use of chemical-based strategies in field management plans. One option is to identify the most chemical-sensitive life stage and tailor management techniques to control that life stage. This would optimize target efficacy while minimizing chemical release into the environment, risk to non-target species, and cost of chemical required. In this study, the relative sensitivity of D. polymorpha life stages was investigated from free gametes to 72-h old trochophores and adults, using cupric sulfate (CuSO₄) and the algaecide, Cutrine®-Ultra. In both forms of copper exposure, early life stages were orders of magnitude more sensitive than adults. For example, the highest 24-h LC₅₀ value for the early life stages to Cutrine®-Ultra was 13 μg Cu/L, while the adult 48-h LC₅₀ value was 1,214 μg Cu/L. Moreover, adults were highly resistant to short-term (24 h) exposures of Cutrine®-Ultra, even at much higher concentrations (4,630 μg Cu/L), while 24-h old D. polymorpha larvae showed 99% mortality after only 52 minutes of exposure to 331 μg Cu/L as Cutrine®-Ultra, a concentration well within the permitted label application. There were only marginal differences in sensitivity to CuSO₄ and Cutrine®-Ultra for larvae tested after fertilization; it is possible that Cutrine®-Ultra is more toxic than CuSO₄ at fertilization. Chemical management strategies targeting early larval stages of D. polymorpha are likely more cost-efficient and less prone to non-target environmental impact than strategies aimed at adults.

The pace of Land Use/Land Cover (LULC) change in the Great Lakes, particularly in urban and suburban areas, far exceeds that predicted by population growth alone. Thus, quantification of LULC and change through time may be a key factor in understanding the near-shore ecology of this system. The work described in this paper is part of a larger effort called the Great Lakes Environmental Indicators Project (GLEI), whose goal was to develop and refine environmental state indicators for the U.S. near-shore zone of the Great Lakes. Here we describe methodologies for using existing Landsat-based LULC maps to assemble consistent LULC data for the U.S. portion of the Great Lakes basin for 1992 and 2001, as well as summarizing salient LULC results. Between 1992 and 2001, 2.5% (798,755 ha) of the U.S. portion of the Great Lakes watershed experienced change. Transitions due to new construction included a 33.5% (158,858 ha) increase in low-intensity development and a 7.5% (140,240 ha) increase in road area. Agricultural and forest land each experienced ∼2.3% (259,244 ha and 322,463 ha, respectively) decrease in area. Despite the large and enduring agricultural losses observed (2.23% of 1992 agricultural area), the rate of agricultural land decrease between 1992 and 2001 was less than that reported by the EPA (−9.8%) for the previous ∼10-year period. Areas of new development were largely concentrated near coastal areas of the Great Lakes. Over 38% (6,014 ha) of wetland losses to development between 1992 and 2001 occurred within 10 km of a coastal area, and most of that area was within the nearest 1 kilometer. Clearly, these land use change data will be especially useful as quantifiable indicators of landscape change over time and aid in future land use planning decisions for protection of the integrity of the Great Lakes ecosystem.

The Cladophora growth model (CGM) was used to estimate the importance of light, temperature, phosphorus, and self-shading on the spatial and temporal variability of Cladophora growth rates and biomass accrual in eastern Lake Erie during 2002. The CGM predicted that Cladophora growth was highly sensitive to spatial and temporal variations in soluble phosphorous concentration (SRP). Specifically the CGM predicted that: 1) Site-to-site differences in SRP concentration resulted in a 2×difference in depth-integrated biomass; 2) maximum growth rates were strongly influenced by SRP concentrations during periods of rapid biomass accrual (mid-June to mid-July); 3) inter-annual differences in SRP concentration during the spring period (∼ 1 μg/L) could result in up to a 3.5×difference in depth integrated biomass; 4) Spatial variations in water clarity could result in a 2×difference in depth-integrated biomass between sites, with variations betweens sites occurring primarily between 2–6 m depth; 5) the midsummer sloughing phenomenon likely resulted from self-shading by the algal canopy; and 6) the seasonal growth pattern of Cladophora was strongly regulated by temperature.

The bloom-forming and toxin-producing cyanobacterium Cylindrospermopsis raciborskii was observed in Muskegon and Mona lakes, drowned river-mouth tributaries of Lake Michigan. Morphological features of the taxon were similar to those described elsewhere. The species was observed only in late summer; elevated bottom water temperature, and perhaps phosphorus concentration, appears to be implicated in its appearance. Maximum abundances at any given site reached 393 and 0.9 trichomes/mL in Mona Lake and Muskegon Lake, respectively. Although these concentrations are low relative to other reports, the presence of this species in these two lakes from adjacent watersheds adds to a growing body of literature that suggests the distribution of C. raciborskii is on the increase in northern latitudes.